its a known bug... hard to fix as well since it's not reproducible, only seems to happen on CoT Oranbegan maps. It's basically one of the CoT portals that appear in the Oranbegan maps, either ones you use to travel through, or one that you have to destroy. I took a screenshot the first time I ever saw it happen:
http://www.mc.maricopa.edu/~byee/aer...rtalglitch.jpg
MA Arcs - #67636, #92202
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I've seen it many times. I always assumed it was supposed to be there for whatever reason.
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Thanks for the information 
We (a SG mate and I) were running missions tonight and we came across this. At first I did not see it, but I exited and reloaded mission and there it was. As well as being there, it rotated in a hurricane type fashion and made a windy noise as well as kind of like an electronic device type hum. I was wondering if you guys have seen anything like this before.
http://i37.tinypic.com/2954ozk.jpg
http://i35.tinypic.com/oq9mon.jpg
http://i33.tinypic.com/1624lr8.jpg